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This post was last edited by Liangsi Qikan Network on 2016-3-23 at 20:31. Some brief thoughts on the layout of industrial pressure pipelines (for reference only). Liangsi Qikan Network: www.liangsiqikan.com 【Abstract】: This article presents some opinions regarding the layout of industrial pressure pipelines. After defining and classifying pressure pipelines, the steps involved in their design are briefly described, and the principles for their layout are outlined: overall planning with local adjustments. It briefly outlines the issues that need attention during pipeline layout, including coordination with various disciplines in pipeline design and stress analysis. Finally, based on personal work experience, it summarizes pipeline layout and presents an understanding of the objectives and requirements for industrial pipeline design, namely economic rationality. 【Keywords】: Pressure pipeline ； Industrial pressure pipelines ； Layout of pressure pipelines ； Economic feasibility ； Preface to pressure pipeline classifications: Pressure pipelines are tubular devices that use pressure to transport gases or liquids. They refer to pipes in which the maximum operating pressure is 0.1 MPa (gauge pressure) or higher for gas, liquefied gas, or steam media; or for liquid media that are flammable, explosive, toxic, corrosive, and have a maximum operating temperature equal to or higher than their standard boiling point; and whose nominal diameter is greater than 25 mm. In industrial production, pressure pipelines are the most widely used. As China’s economy continues to develop at a rapid pace, an increasing number of new factories require engineering design. How to design industrial pressure pipeline layouts that can meet both the owner’s requirements and the needs of production in a short time is a question that every process designer considers. Based on several years of work experience, the following discusses how to install pressure pipelines quickly and effectively, while also taking economic feasibility into account. 1. What is a pressure pipeline? In a broad sense, a pressure pipeline refers to any pipeline that is subjected to internal or external pressure, regardless of the medium contained within it. A pressure pipeline is a part of a piping system; piping systems are used to transport, distribute, mix, separate, discharge, measure, control, and stop the flow of fluids. They consist of pipes, fittings, flanges, bolted connections, gaskets, valves, other components or pressure-bearing parts, as well as supporting elements. Since the issuance of the Regulations on the Safety Management and Supervision of Pressure Pipelines in our country, “pressure pipeline” has become a specific term for pipelines subject to supervision. Article 2 of the Regulations on the Safety Management and Supervision of Pressure Pipelines defines pressure pipelines as: \"special equipment used in production and daily life that may pose significant risks such as fires, explosions, or poisoning.\" The \"Regulations on the Safety Supervision of Special Equipment\" issued and implemented by the State Council on June 1, 2003, further define pressure pipelines as \"tubular equipment that uses a certain pressure to transport gases or liquids. Such pipelines include those with a maximum operating pressure of 0.1 MPa (gauge pressure) or more for gases, liquefied gases, steam, or liquid media that are flammable, explosive, toxic, or corrosive, and whose maximum operating temperature is equal to or higher than their standard boiling point; additionally, these pipelines must have a nominal diameter of 25 mm or more.\" Therefore, the term \"pressure pipeline\" as used today refers not only to pipelines that are under pressure inside or outside them, but also to those in which gases, liquefied gases, and steam, or liquids that may cause combustion, explosion, poisoning, or corrosion, are transported; it is not simply a pressure pipeline in the ordinary sense. In industrial projects, pressure pipelines are the ones that are commonly encountered; therefore, in the design process it is necessary to strictly adhere to the requirements of the \"Regulations on the Safety Supervision of Special Equipment\", and to design the pipelines in accordance with the relevant standards for pressure pipelines. Pressure pipelines are classified into four categories based on their type: long-distance pipelines, utility pipelines, industrial pipelines, and power pipelines. This article focuses on the design aspects related to industrial pipelines (GC category). Industrial pipelines refer to the process pipelines, utility pipelines, and other auxiliary pipelines owned by enterprises and institutions, which are used for transporting process media. Based on the pressure, temperature, and toxicity of the medium being transported, it is further divided into 3 grades. 2. Design of pressure pipelines 2.1 First, determine the category and grade of the pipelines. At the beginning of a new project, communication with the client is carried out to understand the products and production volume involved in the project; the process flow is determined according to the client’s requirements. Based on the definition and classification of pressure pipelines, the category of the pipelines is identified, and their grade is determined based on the properties of the medium used. Finally, according to the unit’s own criteria for classifying pipeline temperatures and pressures, the grade table for the pipelines in this project is established. When determining the process flow, the pipe diameter must be calculated and verified. After completing the above tasks, the layout of the pressure pipes must be carried out. 2.2 Pressure pipeline layout: After determining the pipeline grade table, the pipeline layout is carried out based on the process flow and equipment layout diagrams. The principle of overall layout with local adjustments is followed in this process, which not only saves time but also ensures a rational arrangement of the pipelines. The overall layout involves determining the general path of the pipes based on the boundaries of the equipment area; once the locations of the devices are known, the approximate positions of each pipe can be determined ； Local adjustments are made to the pipe positions after the design is largely completed, through consultation and coordination with various relevant specialties. In the design, if the process pipes collide with utility pipes or beams and columns, local adjustments to the pipe elevation or route are required. If the connections of the equipment pipes change, the pipes also need to be adjusted. In cases where there are no major changes, the overall layout remains unchanged; only the relevant pipes are modified. The placement of pipes is not determined in one go; the nature of engineering design means that the drafting process is not completed in a single step and requires constant modifications. By following the principles mentioned above for pipe arrangement, adjustments may be necessary depending on the circumstances, but this approach saves labor and time throughout the design process, resulting in a more reasonable layout of the pipes. This principle is particularly applicable to construction projects for which the structural layout is determined first; the piping arrangement can be carried out based on the already established equipment layout plan, starting with the main pipes and then the branch pipes. After the general layout of the main pipes is finalized, the specific locations of the branch pipes are determined according to the connections of the equipment, with any necessary adjustments made as needed. 2.3 Communication and coordination with relevant specialties: Coordination with these specialties is carried out to adjust the pipeline layout, and this process also takes place concurrently during the design phase. 2.4 Stress analysis of pressure pipelines: For certain pipelines with large diameters and high pressures, stress analysis is required at branch points and bends. Make appropriate adjustments to the pipe diameter and wall thickness. The above only briefly covers the general steps of pipeline design; in more complex pipeline designs, the diameter of the pipes and the head parameters of the pumps must be determined based on the production volume of the engineering project. In summary, the economic viability of pipeline layout is a key factor to consider in design. Under the premise of meeting production needs and client requirements, how to complete the pipeline design in a short time is a question that every designer must address. In practical work, adopting the principle of overall layout with local adjustments not only saves time but also avoids unnecessary waste of effort. 3. Some issues to consider in pipeline layout design: For pressure pipelines, due to the different properties of the media transported, safety aspects related to factors such as pressure, temperature, and the toxicity of the media must be taken into full account during design. Such as the installation location of valves, the installation of pressure gauges, flow meters, etc., whether the location of safety relief devices is easy to operate, whether the positions of pipe supports and hangers are appropriate, and the installation of buffer devices in areas where stress concentration occurs. The layout of process pipelines is a meticulous task that requires patience and care. Define the objectives at the initial design stage, have a rough idea in mind of the main pipeline route based on the equipment layout diagram, and consider whether an intermediate pipe gallery is needed. Secondly, become familiar with the standard specifications for piping, including the spacing between adjacent pipes, the distance between pipes and nearby structures, the installation of pipe racks, and the height of valve handles. Third, arrange things reasonably and start drawing to refine the equipment layout diagram; referring to the process flow diagram, begin with the main pipelines first. Piping work begins in accordance with the principle of making local adjustments to the overall layout. Fourth, select materials appropriately – they should meet the process requirements without being overly conservative and resulting in waste. Finally, accurately count the materials. Care must be taken with statistical data; using the wrong materials during construction is the most embarrassing situation for many piping designers. Accurate material statistics also provide a solid basis for the owner’s bidding process, enabling cost savings during the construction of the project and helping to achieve economic rationality for it. In today’s era of rapid economic development, cost-effectiveness is a major concern for every owner. As designers, the starting point for creating drawings is the owner’s requirements for the project. Therefore, economic rationality plays a key role throughout the design process. A qualified engineering designer must not only be able to complete tasks on time but also ensure that the designed drawings are cost-effective and easy to implement, thereby meeting the owner’s requirements while saving time and resources. Only drawings that can achieve such goals can be considered proper pipe layout diagrams. References: [1] Code for Design of Industrial Metal Piping GB50316-2000 [2] Code for Pressure Piping GB/T20801-2006